In project two we explore how force regulates subcellular organization of adhesion molecules to promote acini morphogenesis. While a reductionist approach is typically used to clarify the molecular mechanisms that drive development and maintain homeostasis, we take the view that cell and tissue behavior are phenotypically plastic, mediated by adhesion and modified by mechanical force. We are testing the idea that force regulates the organization of proteins at the subcellular level to alter cellular organization at the tissue level but that emergent properties of multi cellular tissues and feedback mechanisms alter the responsiveness of cells to mechanical cues. We will test this idea by investigating the mechanisms by which mechanical force regulates acinar morphogenesis and stability. We will test whether force modulates integrin clustering, to drive fecal adhesions and enhance growth factor receptor signaling to modify acinar polarity and morphology. We will achieve this using cell biological approaches that assay signaling and acini behavior, through the use of engineered matrices and applied shear force and through PALM and TIRF imaging of integrin clustering and in response to modifications in cell surface glycoproteins, ligand density and cytoskeletal manipulations. We will also quantify how mechanical forces spread though 'normal'acinar structures te understand hew cells respond to and transmit forces within at tissue and investigate hew signaling mechanisms mediated through cell-cell and cell-ECM interactions synergize to regulate tissue homeostasis. This will be achieved by using biophysical techniques to mechanically perturb the system (AFM and subcellular laser ablation) and by then watching the system respond using genetically directed force-sensitive optical probes. Finally we will build models to test the concept that cells exhibit an integrated response to force and that this response is governed by emergent properties of multi cellular tissues. This will be achieved by modifying existing chemical-adhesion models and also building an integrated but simplified model, informed by molecular details, that simulates the whole system and that spans multiple spatial and temporal scales.